1. Field of the Invention
The invention concerns a ring binder mechanism with a housing having a C-shaped or U-shaped cross-section, with elastic mounting flanks which can be bent open for receiving two carrier rails, which on their facing longitudinal edges lie against each other with formation of a linkage axis, and which with their away-facing longitudinal edges engage in mounting grooves of the mounting flanks, and with at least two half-rings rigidly connected with the carrier rail in a defined longitudinal separation from each other, extending through openings in a housing wall and forming themselves pairwise into a ring, wherein the carrier rails are limitedly pivotable relative to each other about the longitudinal pivot axis between an open position and a closed position, while overcoming the spring force produced by the bending open of the mounting shanks, and while taking along the half-rings, and wherein at least one blocking element is provided displaceable or moveable relative to the housing essentially parallel to longitudinal pivot axis and to the carrier rails via an operating element, which blocking element when in the closed position engages in a free space formed between the carrier rails and the housing wall thereby blocking the pivot movement, and when in the open position releases the linkage axis to pivot.
2. Description of the Related Art
In ring binder mechanisms it is known to secure half-rings arranged in a row upon carrier rails, which are surrounded by a housing of a spring elastic material. The carrier rails are so introduced into the housing that they can assume two rest positions, one open and one closed. The housing functions as a spring element, which retains the half-rings in their open position or in their closed position. In the area of the inner longitudinal edges of the carrier rails, there are take-along or engaging means, which ensure that the two carrier rails along these longitudinal edges are always lying flush against each other. The carrier rails thereby have the function of a knee-lever held in spring tension by the outer edge. With these known ring notebook mechanisms the opening and closing of the rings occurs directly via the half-rings. In order to attain sufficient pretension or pull forces, it is necessary to have a relatively large spring force in the area of the housing. The necessary operating forces must be commensurately large. The greater these forces are, so much the greater is also the danger of injury during closure at the abutment surfaces between the ring-halves. On the other hand, since the closure forces are exclusively introduced elastically, it frequently occurs that the rings in response to a particular stress, for example, during falling onto the floor, open from themselves, so that the therein situated writing materials can be released.
In order to avoid this disadvantage, it has already been proposed to secure the rings in their closed position using a sliding element (U.S. Pat. No. 4,566,817). The sliding element exhibits blocking elements slideable parallel to the linkage axis relative to the housing and to the carrier rails, which engage in the locking position into a free space formed between the carrier rails and the housing wall to block the pivot movement of the carrier rails, and in the open position unblock the pivot path. The sliding element is moved between the open position and the locked position by hand. Also possible are intermediate positions without function. For operating the sliding element the binder must be laid down somewhere or held. Two hands are necessary to do this. From the open position this ring binder mechanism cannot be closed or operated via the rings.